Implement Mac Pop-up Dictionary for OOPIF.

content/renderer/render_widget.h

Index: content/renderer/render_widget.h
diff --git a/content/renderer/render_widget.h b/content/renderer/render_widget.h
index ee17345dcec6bcede9f107a1daf89ed473559e8a..daf990530e974ffd2a9160b025dc7637032f4fe2 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -394,6 +394,9 @@ class CONTENT_EXPORT RenderWidget
     return mouse_lock_dispatcher_.get();
   }
 
+  // TODO(ekaramad): The reference to the focused pepper plugin will be removed
+  // from RenderWidget. The purpose of having the reference here was to make IME
+  // work for OOPIF (https://crbug.com/643727).
   void set_focused_pepper_plugin(PepperPluginInstanceImpl* plugin) {
     focused_pepper_plugin_ = plugin;
   }